Re: [PATCH V4 4/4] arm64: dts: qcom: sm8550: Remove SDR104/SDR50 broken capabilities

[Krzysztof Kozlowski <krzk@kernel.org>]

On 05/08/2025 11:19, Sarthak Garg wrote:
> 
> 
> On 8/1/2025 2:32 PM, Krzysztof Kozlowski wrote:
>> On 01/08/2025 10:45, Sarthak Garg wrote:
>>> The kernel now handles level shifter limitations affecting SD card
>>> modes, making it unnecessary to explicitly disable SDR104 and SDR50
>>> capabilities in the device tree.
>>>
>>> However, due to board-specific hardware constraints particularly related
>>> to level shifter in this case the maximum frequency for SD High-Speed
>>> (HS) mode must be limited to 37.5 MHz to ensure reliable operation of SD
>>> card in HS mode. This is achieved using the max-sd-hs-frequency property
>>> in the board DTS.
>>>
>>> Signed-off-by: Sarthak Garg <quic_sartgarg@quicinc.com>
>>> ---
>>>   arch/arm64/boot/dts/qcom/sm8550-hdk.dts                     | 1 +
>>>   arch/arm64/boot/dts/qcom/sm8550-mtp.dts                     | 1 +
>>>   arch/arm64/boot/dts/qcom/sm8550-sony-xperia-yodo-pdx234.dts | 1 +
>>>   arch/arm64/boot/dts/qcom/sm8550.dtsi                        | 3 ---
>>>   4 files changed, 3 insertions(+), 3 deletions(-)
>>>
>>
>> This will break MMC for all of the users and nothing in commit msg or
>> cover letter explains that or mentions merging strategy.
>>
>> Exactly this case is covered by your internal guideline, no? Please read it.
>>
>> Best regards,
>> Krzysztof
> 
> Just to make sure I’m addressing the right concern — are you primarily 
> worried about the introduction of the max-sd-hs-frequency property in 
> the board DTS files, or about the removal of the sdhci-caps-mask
> from the common sm8550.dtsi?


Apply this patch and test MMC. Does it work? No. Was it working? Yes.


Best regards,
Krzysztof